Spontaneous decay of excited cold atoms into cavity can drastically affect their translational dynamics, namely, atomic reflection, transmission or localization in the cavity.
We study spontaneous radiative decay of translational levels of an atom in the vicinity of a semi-infinite dielectric. We systematically derive the microscopic dynamical equations for the spontaneous decay process. We calculate analytically and numerically the radiative linewidths and the spontaneous transition rates for the translational levels. The roles of the interference between the emitted and reflected fields and of the transmission into the evanescent modes are clearly identified. Our numerical calculations for the silica-cesium interaction show that the radiative linewidths of the bound excited levels with large enough but not too large vibrational quantum numbers are moderately enhanced by the emission into the evanescent modes and those for the deep bound levels are substantially reduced by the surface-induced redshift of the transition frequency.
Remarkable quantum effects are predicted for an initially excited two-level wave packet incident on a broadband vacuum-field reservoir with sharp spatial boundaries: (a) reflection of the excited wave packet from the boundary (skin effect); (b) transient three-dimensional binding of the decayed wave packet to the boundary by photons carrying more energy than the incident wave packet. These effects are realizable for cold atoms in cavities where excitation decay is nearly exponential but strongly enhanced.